V4L/DVB (5133): M920x: move qt1010_tuner_attach function into qt1010.h

The megasky_tuner_attach function is not specific to this device.
This patch renames it to qt1010_tuner_attach and moves it into the qt1010
header file.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>